====== Summary of Main Bash Scripting Concepts and Commands ======

Bash (Bourne Again Shell) is a powerful command-line interpreter commonly used in Linux and Unix environments. Below is a summary of essential Bash commands and scripting concepts.

===== Basic Commands =====
  * **[[bash:commands:echo|echo]]** - Outputs text to the terminal. Example: `echo "Hello, World!"`
  * **[[bash:commands:pwd|pwd]]** - Prints the current working directory.
  * **[[bash:commands:ls|ls]]** - Lists the contents of a directory. Example: `ls -l`
  * **[[bash:commands:cd|cd]]** - Changes the working directory. Example: `cd /home/user`
  * **[[bash:commands:cp|cp]]** - Copies files or directories. Example: `cp source.txt destination.txt`
  * **[[bash:commands:mv|mv]]** - Moves or renames files or directories. Example: `mv old.txt new.txt`
  * **[[bash:commands:rm|rm]]** - Removes files or directories. Example: `rm file.txt`
  * **[[bash:commands:touch|touch]]** - Creates an empty file or updates a file's timestamp. Example: `touch newfile.txt`

===== Variables and Parameters =====
  * **[[bash:variables:definition|Variable Definition:]]** Assigns values to variables. Example: `name="John"`
  * **[[bash:variables:usage|Variable Usage:]]** References variables using `$`. Example: `echo $name`
  * **[[bash:variables:read|User Input:]]** Reads user input. Example:
    ```
    read name
    echo "Hello, $name!"
    ```

===== Conditionals =====
  * **[[bash:conditionals:if_else|if-else Statements]]** - Executes commands based on conditions:
    ```
    if [ "$name" = "John" ]; then
      echo "Hello, John!"
    else
      echo "Who are you?"
    fi
    ```
  * **[[bash:conditionals:case|case Statements]]** - Matches patterns to execute specific commands:
    ```
    case $fruit in
      apple) echo "This is an apple";;
      banana) echo "This is a banana";;
      *) echo "Unknown fruit";;
    esac
    ```

===== Loops =====
  * **[[bash:loops:for|for Loop]]** - Iterates over a list of items:
    ```
    for i in 1 2 3; do
      echo "Number: $i"
    done
    ```
  * **[[bash:loops:while|while Loop]]** - Repeats commands while a condition is true:
    ```
    count=0
    while [ $count -lt 5 ]; do
      echo "Count: $count"
      count=$((count + 1))
    done
    ```

===== Functions =====
  * **[[bash:functions:definition|Defining Functions]]** - Groups commands into reusable functions:
    ```
    greet() {
      echo "Hello, $1!"
    }
    greet "Alice"
    ```
  * **[[bash:functions:return_values|Returning Values]]** - Functions can return status codes using `return`.

===== Input/Output Redirection =====
  * **[[bash:io:redirection|Redirection]]** - Redirects output to a file. Example: `echo "Text" > output.txt`
  * **[[bash:io:append|Appending Output]]** - Appends output to a file. Example: `echo "More text" >> output.txt`
  * **[[bash:io:stdin|Standard Input (stdin)]]** - Redirects input from a file. Example: `cat < input.txt`
  * **[[bash:io:pipe|Piping]]** - Passes the output of one command as input to another. Example: `ls | grep "file"`

===== File Management =====
  * **[[bash:files:test|File Testing]]** - Tests file conditions. Example:
    ```
    if [ -f "file.txt" ]; then
      echo "File exists"
    fi
    ```
  * Common file tests:
    * `-f` - Checks if a file exists and is regular.
    * `-d` - Checks if a directory exists.
    * `-r` - Checks if a file is readable.
    * `-w` - Checks if a file is writable.

===== Process Management =====
  * **[[bash:processes:background|Background Processes]]** - Runs a command in the background using `&`. Example: `sleep 10 &`
  * **[[bash:processes:jobs|jobs]]** - Lists background jobs.
  * **[[bash:processes:kill|kill]]** - Terminates a process. Example: `kill 1234`

===== Error Handling =====
  * **[[bash:error_handling:exit_status|Exit Status]]** - The exit status of the last command can be accessed using `$?`.
  * **[[bash:error_handling:set|set -e]]** - Stops script execution on any error.

===== Comments =====
  * **[[bash:comments:single_line|Single-line Comments]]** - Starts with `#`. Example: `# This is a comment`
  * **[[bash:comments:multi_line|Multi-line Comments]]** - Use multiple `#` lines for multi-line comments.

This summary covers the fundamental concepts of Bash scripting. Each section can be expanded with detailed examples and explanations.